1. Field of the Invention
This invention relates generally to pistons for internal combustion engines, and methods of manufacturing the same.
2. Related Art
Pistons used in internal combustion engines should be designed with appropriate contact geometry for sliding along a cylinder of the internal combustion engine. Oftentimes, an outside running surface, such as the surface of a piston skirt, is machined to an oval shape, in cross-section, to meet such requirements. However, the process of machining the metal material of the piston to the desired oval shape is expensive and requires specialized equipment.
Wrist pin bores of pistons are also typically formed to an appropriate shape, such as a non-round shape, for accommodating a wrist pin as the piston reciprocates in the cylinder of the engine. This profiled wrist pin bore is also expensive to manufacture, due to the process steps and equipment required to machine the metal material.